1. Technical Field
The present invention relates generally to motor vehicle induction systems, and more particularly to a method of designing a motor vehicle induction system that minimizes the amount of engine noise emitted by that system.
2. Discussion
It is desirable to design an engine induction system such that engine noise emitted by the system is minimized. Conventionally, emitted system noise is minimized through implementation of an objective, or cost, function defined by several objective parameters. Typically, total sound pressure level (SPL), often referred to as dB(A) noise level, is engine noise emitted by the engine through the induction system weighted by human ear perception characteristics, and is the most commonly used objective parameter. Unweighted SPL can alternatively be utilized in place of weighted SPL. Another objective parameter that may be utilized is total loudness as defined by International Standards Organization (ISO) R 532b recommendation. Further, induction system dimensions may also be utilized in the objective function, as well as system component volumes and/or lengths.
The function as defined by the above parameters can thus be used to minimize noise levels associated with the system. The function may also be used to minimize system dimensional requirements, and thus production costs and space requirements for an induction system.
Conventionally, the above function has been implemented through trial and error adjustment of the above mentioned parameters. Therefore, overall system optimization is difficult to achieve, as adjustment of each of the numerous parameters in the function affects the weighting factor associated with the other function parameters.
Also, software engine and induction system modeling programs exist that allow an engine and induction system to be modeled as a noise source. Software programs also exist that allow induction system part sizes and locations to be modeled. However, no methods exist that allow objective parameters such as those mentioned above to be weighted according to specified design criteria to allow different systems to be designed for different engines. Also, numerous trial and error iterations must be run to generate a system model. Each iteration could lead to degradation in system design rather than an improvement, due to the inherent subjectiveness involved in changing system parameters in the existing programs.